I think you are going to have to rely on another human being (or perhaps a group of trusted individuals) even in that case. Depending upon what caused your incapacitation, you may or may not be able to actually retain and manage your secrets going forward. Put another way, if your wetware is damaged you may need a backup (aka trusted human) to handle your secrets on your behalf.
Shamir's secret sharing is the algorithm for splitting a key and requiring only a subset of pieces (so you can disperse it to 20 friends but only need 11 to agree to reform the key).
This would give you protection both against the amnesia route (where you fall unconscious, lose your memory but are totally fine afterwards) and the route where you're unable to manage your secrets at all (eg stroke resulting in longterm failure to maintain memories or make decisions).
You'd still, for the total lose route, need a replacement actor (someone acting on your behalf) to assemble and receive the key, and be the keyholder moving forward - and you would likely need to leave instructions with the flock of people having pieces of the key on how to select or confirm your future keyholder.
I think you are going to have to rely on another human being (or perhaps a group of trusted individuals) even in that case.
Not necessarily. Bank safe-deposit boxes are a secure place to keep secrets. To guard against rogue bank employees, encrypt the stored secrets and keep the key at home on a sticky note. If you ever hit your head and forget all your secrets, just present your ID to the bank teller, pull the secrets out of the vault, and decrypt them with the key on the sticky note.
